1. Field of the Invention
The present invention relates to an improvement of heat resistant cloth for fire fighting suitable for use in fireproof suits worn by firemen at the site of fire.
2. Description of the Related Art
A conventional heat resistant cloth for fire fighting is disclosed in Japanese Utility Model Publication (kokoku) No. 62-34765. As shown in FIG. 2, the conventional heat resistant cloth for fire fighting has a rubber layer 2 disposed on the outer surface of a substrate fabric 1 made of an aramid fiber or the like. A polyester film 4 having aluminum deposition films 3 and 5 on opposite sides thereof is bonded to the surface of the rubber layer 2 via a first bonding layer 6. A tetrafluoroethylene copolymer film 8 is bonded to the outside deposition film 3 via a second bonding layer 7.
In the conventional heat resistant cloth for fire fighting, in consideration of fabric workability, a polyester film is used for formation of deposition films through vacuum-deposition, which deposition films are provided for enhancement of heat reflectivity. However, when the heat resistant cloth for fire fighting is sewn to fabricate a firemen's suit, the polyester film is subjected to tension, with the result that the deposition films breaks and separates from the polyester film at a seam, which in turn results in deterioration of weather resistance and texture. To solve these drawbacks, the tetrafluoroethylene copolymer film serving as a protective layer is bonded to the surface of the polyester film having the deposition films.
Another conventional heat resistant cloth for fire fighting is disclosed in Japanese Patent Application Laid Open (kokal) No. 9-19412. As shown in FIG. 3, a synthetic rubber layer 10 is disposed on the surface of a substrate fabric 9, and a heat reflecting layer 15 is bonded to the surface of the rubber layer 10 via a bonding layer 11. The heat-reflecting layer 15 is composed of a tetrafluoroethylene copolymer film 14 having an inner surface 14a subjected to corona discharge treatment, and a vacuum-deposition film 12 of aluminum or the like formed on the inner surface 14a via a primer coating layer 13.
In the heat resistant cloth for fire fighting shown in FIG. 3, the weights of the substrate fabric and the synthetic rubber are reduced in order to reduce the overall weight of the heat resistant cloth. Moreover, in order to obtain soft texture and enhanced flame resistance, the polyester film of the heat resistant cloth for fire fighting shown in FIG. 2 is omitted. Instead, a tetrafluoroethylene copolymer film--which has conventionally been used as a protective layer--is used as a layer for supporting a deposition film. That is, after the inner surface of the tetrafluoroethylene copolymer film is subjected to corona discharge treatment, a deposition film is applied to the inner surface of the tetrafluoroethylene copolymer film via a primer coating layer. Subsequently, the tetrafluoroethylene copolymer film is bonded to a substrate fabric via a bonding layer.
The conventional heat resistant cloth for fire fighting shown in FIG. 3 has an improved structure such that a tetrafluoroethylene copolymer film is used to make the texture soft and enhance flame resistance; the copolymer film surface is subjected to corona discharge treatment to produce a sufficient degree of adhesiveness between the copolymer film and the deposition film; and the deposition film is formed on the copolymer film via the primer coating layer made from a synthetic resin and the thus completed heat reflecting layer 15 is bonded to the substrate fabric in order to obtain sufficient brightness to thereby achieve required heat reflectivity. However, since the heat resistance of the synthetic resin is low, the conventional heat resistant cloth causes problems at high temperature in that cracks are generated in the cloth and heat reflectivity is lowered due to decreased brightness.
Moreover, the conventional heat resistant cloths shown in FIGS. 2 and 3 have the problem that they are thick and heavy, because a rubber layer is disposed on the surface of the substrate fabric.
The conventional heat resistant cloths use an adhesive which is made of an acrylic resin, a urethane resin, or an ethylene vinylacetate resin, to which is added a flame retardant, such as aluminum hydroxide, antimony oxide, a bromic compound, or a phosphoric compound. However, there still exists the problem that the adhesiveness is low at high temperature.